I have just finished making my very first bash script. It’s called Simple Log File Monitor as you may have guessed.
It reads in a log file, either from the beginning or from a mark that the script has set before, then it can perform a user defined action to the output of the log file after it has been read.
It will then apply an action to the resultant output of the logfile, e.g. email it to you.

I have written it in shell script in order for it to be small, and as reliant on as little as possible.
You should be able to run this script with just bash, awk, grep, tail, date, and wc.
The purpose of this was for a router that I plan to build. I didn’t want to install perl onto it as it will have miniscule storage, so I thought this was a better option. This script should also work on any embedded devices that have the required utilities installed, so if there is anyone out there who has one of those, I’d appreciate any testing that could be done on those devices.

This script allows you to set a configuration file with the -c switch when you run the script, but if you don’t set it, the script will use the default slfm.conf that should be located in the same directory as the script itself.

This allows you to customise when the log file is monitored, and which files are monitored by running the script at certain intervals with different command line parameters.
So the script will show the last hours worth of logs if the script is run hourly.

The script will mark it’s position so that it won’t have to read the whole entire logfile again, and then it can redirect the output of the logfile to anywhere. For example it can email you the results, or it can append the results to a file.

The documentation on this isn’t great at the moment so any help with that would be appreciated.
If anyone could please try this script out and provide feedback in the comments section, that would be great.
As this is my first script, please be gentle 😀 but I’m open to any suggestions on how to make this better.

This script can be downloaded from my sourceforge page.
It has a sample configuration file already included to help you get started. Hopefully it’s understandable enough and clear enough to everyone and easy enough to work with.
Hope to hear back from some new users 😀